1. Field
The present disclosure relates generally to data processing system networks on mobile platforms, such as aircraft, and, more particularly, to systems and methods for monitoring traffic on such networks.
2. Background
Aircraft network data processing systems can be very complex. For example, aircraft network data processing systems may be used to process various parameters while the aircraft is in flight and to provide aircraft control, alerting functions, and maintenance reports. Connectivity may be provided between the on-board aircraft network data processing system and ground-based data processing systems or networks outside of the aircraft. For example, such connectivity allows an airline or other entity to provide advanced maintenance diagnostics and situational awareness that may not be provided on the aircraft itself.
Such connectivity also allows the aircraft to provide to the ground-based entity data gathered or generated by the aircraft while the aircraft is in flight. This data may include, for example, meteorological data, airspeed, location of the aircraft while in flight, as well as other similar data for the aircraft in flight.
The Aircraft Communications Addressing and Reporting System (ACARS) uses satellite connectivity for aircraft communications. This system provides a data channel for transmission of short messages to and from the flight deck of an aircraft. This system has been used for data transmissions for a variety of applications. This system is a precursor to the high speed communications links that are now starting to be used for air-to-ground connectivity in commercial airline fleets.
Examples of current systems for air-to-ground connectivity to aircraft include terrestrial and satellite networks using L band, Ku band, and Ka band. In addition to these systems, connectivity from an aircraft-to-ground-based system may include terminal wireless communications using Wi-Fi, cellular networks, and Wi-Max technologies. These systems may utilize commercial technologies and use Internet Protocol and Ethernet protocols for the connectivity.
As technologies and computing architectures have evolved, so have the data bus structures that are used for network data processing systems on aircraft. As network computing first became prevalent, simple data bus protocols were developed and deployed to commercial aircraft. Since digital interfaces were introduced in the late 1970s, aircraft have used both data buses and protocols that were designed specifically for aviation applications and data buses and protocols that were adapted for aviation applications from other commercial applications. These aviation-specific buses and protocols were not necessarily proprietary but still had limited exposure to the general public. Examples of such data buses include data buses defined by standards, such as RS-485, ARINC 429, MIL-STD-1553, and ARINC 629, among others. RS-485 and ARINC 429 data buses employ a one-way serial bus. MIL-STD-1553 data buses employ a bus structure with a centralized controller. ARINC 629 data buses employ a two-way transmit and receive bus. Many data buses of these types are still in use on existing aircraft and are being used in new aircraft designs. A feature of these data buses is a specific aviation application and targeted system communications.
As consumer technologies have advanced, many designs for data buses used in aircraft have evolved from a supplier-based proprietary design to a commercial off-the-shelf based design. Rather than invent new technologies, aircraft suppliers have already deployed and tested commercial off-the-shelf technologies. Such use of commercial technology provides large gains with system designs utilizing processor-based hardware and common hardware based platforms for hosting software functionality. Specific aircraft interfaces may be designed into these systems and easily interfaced with the commercial off-the-shelf technology.
One of the commercial technologies that has taken hold in aircraft applications is Ethernet networks. Ethernet networks and protocols were devised in the early 1980s and have remained somewhat stable at the basic network layer. Currently, Ethernet features advanced protocols capable of large bandwidth and information exchange.
The Ethernet protocol has been adopted for various aviation applications. This protocol became the basis for the bulk of broadband airborne and ground-based aircraft connectivity, especially in the passenger cabin of commercial aircraft. As new aircraft were introduced, Ethernet networks gained wider use in avionics systems, replacing some of the older protocol networks.
As Ethernet networks are introduced into an aircraft, the standard aircraft design process still must be adhered to. For example, a functional hazard assessment must be performed for each aircraft system. This assessment must address all interfaces and software at the appropriate level. For example, critical systems with non-essential system interfaces must account for that in their system design. This means that failure modes or false data would be accounted for in the basic design process. Adding a different network protocol or interface does not change the basic design methodology. However, the different network protocol or interface will have logic and other source data to validate the data or use it in a manner that does not impact a critical function.
Network data processing systems on aircraft may provide isolation of critical systems from other systems on the aircraft. For example, an ARINC 629 type data bus provides a gateway function designed to isolate systems and data streams. Communications between systems on an ARINC 629 bus and other systems in an electronic library system may be routed through an aircraft information management system cabinet. The aircraft information management system cabinet may provide, for example, Ethernet, ARINC 629, and ARINC 429 interfaces, with gateways and processor modules to transfer data among them.
Recent Ethernet network architectures used in aircraft have followed a similar model. The ARINC 664 network standard was developed at the aircraft industry level to define specific control zones or domains and to isolate and provide a controlled interface between these domains. These domains include an aircraft control domain, an airline information services domain, and a passenger information and entertainment services domain.
Communications between these domains may be managed and monitored to ensure the appropriate isolation between domains. For example, communications between the domains may be managed and monitored using mechanisms, such as standard information technology industry switching and routing with port monitoring and virtual private networks employing encrypted tunnels between secure end points. With these different domains, access to the network data processing system on the aircraft has become more of a concern. Unauthorized access may affect the performance of the aircraft. Also, unauthorized access may allow unauthorized persons to access proprietary information, such as data and programs on the aircraft network processing system.
Accordingly, it would be advantageous to have a method and apparatus that takes into account one or more of the issues discussed above, as well as possibly other issues.